<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
	<style type="text/css">
		div{
			width: 200px;
			height: 200px;
			background: skyblue;
			padding: 20px;
			border: 5px solid red;
			margin: 20px;
			box-sizing: border-box;
            /*		
                  box-sizing: border-box; 怪异盒子模型

                  css3新属性：保证了边框、内边距的同时，元素的整体宽高不变

                  border-box： 元素宽高 = 内容大小 (width、height)


            	*/
		}
	</style>
</head>
<body>
      <div>
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      	sdakhjas
      	sd;kajdl
         sdadjlas
      	sdsajdklsa
      	kjsahdsao
      	sajhdhiuaskj
      	skaljjdjoaix
      	xz;lmkjcsaiofjo
      	salklbsah
      </div>

      
</body>
</html>